Added OpenTracing support; fixes #599

docs/src/main/asciidoc/features.adoc

@@ -39,14 +39,14 @@ a baggage element then it will be sent downstream either via HTTP or messaging t
 
 * Provides a way to create / continue spans and add tags and logs via annotations.
 
-* Provides simple metrics of accepted / dropped spans.
-
 * If `spring-cloud-sleuth-zipkin` then the app will generate and collect Zipkin-compatible traces.
 By default it sends them via HTTP to a Zipkin server on localhost (port 9411).
 Configure the location of the service using `spring.zipkin.baseUrl`.
   - If you depend on `spring-rabbit` or `spring-kafka` your app will send traces to a broker instead of http.
   - Note: `spring-cloud-sleuth-stream` is deprecated and should no longer be used.
 
+* Spring Cloud Sleuth is http://opentracing.io/[OpenTracing] compatible
+
 IMPORTANT: If using Zipkin, configure the percentage of spans exported using `spring.sleuth.sampler.percentage`
 (default 0.1, i.e. 10%). *Otherwise you might think that Sleuth is not working cause it's omitting some spans.*
 

docs/src/main/asciidoc/spring-cloud-sleuth.adoc

@@ -931,6 +931,12 @@ on how to create a Stream Zipkin server.
 
 == Integrations
 
+=== OpenTracing
+
+Spring Cloud Sleuth is http://opentracing.io/[OpenTracing] compatible. If you have
+OpenTracing on the classpath we will automatically register the OpenTracing
+`Tracer` bean. If you wish to disable this just set `spring.sleuth.opentracing.enabled` to `false`
+
 === Runnable and Callable
 
 If you're wrapping your logic in `Runnable` or `Callable` it's enough to wrap those classes in their Sleuth representative.

spring-cloud-sleuth-core/pom.xml

@@ -152,6 +152,11 @@
 			<groupId>io.zipkin.brave</groupId>
 			<artifactId>brave-instrumentation-spring-webmvc</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>io.opentracing.brave</groupId>
+			<artifactId>brave-opentracing</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<!-- BRAVE -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/opentracing/OpentracingAutoConfiguration.java

@@ -0,0 +1,34 @@
+package org.springframework.cloud.sleuth.instrument.opentracing;
+
+import brave.Tracing;
+import brave.opentracing.BraveTracer;
+import io.opentracing.Tracer;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration Auto-configuration}
+ * to enable tracing via Opentracing.
+ *
+ * @author Spencer Gibb
+ * @author Marcin Grzejszczak
+ * @since 2.0.0
+ */
+@Configuration
+@ConditionalOnProperty(value="spring.sleuth.opentracing.enabled", matchIfMissing=true)
+@ConditionalOnBean(Tracing.class)
+@ConditionalOnClass(Tracer.class)
+@EnableConfigurationProperties(SleuthOpentracingProperties.class)
+public class OpentracingAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean
+	Tracer sleuthOpenTracing(brave.Tracing braveTracing) {
+		return BraveTracer.create(braveTracing);
+	}
+}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/opentracing/SleuthOpentracingProperties.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2013-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.sleuth.instrument.opentracing;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * Sleuth Opentracing settings
+ *
+ * @since 2.0.0
+ */
+@ConfigurationProperties("spring.sleuth.opentracing")
+public class SleuthOpentracingProperties {
+
+	private boolean enabled = true;
+
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
+}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/TraceWebFilter.java

@@ -32,7 +32,7 @@
  * @author Marcin Grzejszczak
  * @since 2.0.0
  */
-public class TraceWebFilter implements WebFilter, Ordered {
+public final class TraceWebFilter implements WebFilter, Ordered {
 
 	private static final Log log = LogFactory.getLog(TraceWebFilter.class);
 

spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories

@@ -18,7 +18,8 @@ org.springframework.cloud.sleuth.instrument.reactor.TraceReactorAutoConfiguratio
 org.springframework.cloud.sleuth.instrument.web.TraceWebFluxAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.zuul.TraceZuulAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.messaging.TraceSpringIntegrationAutoConfiguration,\
-org.springframework.cloud.sleuth.instrument.messaging.websocket.TraceWebSocketAutoConfiguration
+org.springframework.cloud.sleuth.instrument.messaging.websocket.TraceWebSocketAutoConfiguration,\
+org.springframework.cloud.sleuth.instrument.opentracing.OpentracingAutoConfiguration
 
 # Environment Post Processor
 org.springframework.boot.env.EnvironmentPostProcessor=\